The present invention relates to a method of producing a semiconductor device and a method of producing the semiconductor device. More specifically, the present invention relates to a Schottky diode and a method of producing the Schottky diode.
In a Schottky diode, a metal is connected to a semiconductor to create a Schottky barrier, so that the Schottky barrier is utilized in the Schottky diode. In the Schottky diode, a large number of carriers operate. Accordingly, as opposed to a normal PN connection diode, a voltage decrease in a forward direction is relatively small, thereby achieving a high switching speed. For this characteristic, the Schottky diode has been widely used for a standard logic IC to increase an operational speed thereof, a power source of an audio apparatus, or a switching power source.
Patent Reference has disclosed a conventional Schottky diode.    Patent Reference: Japanese Patent Publication No. 2003-229570
FIG. 1 is a schematic sectional view showing a configuration of the conventional Schottky diode disclosed in patent Reference. As shown in FIG. 1, the conventional Schottky diode includes an N-type epitaxial layer 10; an N+ embedded diffusion layer 12; an N− diffusion layer 14; a P− diffusion layer 16; a P+ diffusion layer 18; and a metal layer 20.
In the conventional Schottky diode shown in FIG. 1, an anode is formed of the metal layer 20 disposed on an N-type substrate, thereby constituting a Schottky barrier diode. A peripheral area of the anode is surrounded with the P− diffusion layer 16. A cathode is drawn through the embedded diffusion layer 12 and the N− diffusion layer 14 for separating elements, thereby reducing a parasitic resistivity.
In the conventional Schottky diode shown in FIG. 1, the P− diffusion layer 16 is provided for alleviating an electrical filed concentration at an end portion of the conventional Schottky diode. Accordingly, a reverse voltage resistance of the conventional Schottky diode is determined by a distance between the P− diffusion layer 16 and the embedded diffusion layer 12.
In other words, the reverse voltage resistance of the conventional Schottky diode is determined by a thickness of the N-type epitaxial layer 10. Accordingly, when it is necessary to obtain a desirable reverse voltage resistance (or obtain a reverse voltage resistance greater than that determined by a normal thickness of the N-type epitaxial layer 10), it is necessary to increase the thickness of the N-type epitaxial layer 10.
In the conventional Schottky diode shown in FIG. 1, the thickness of the N-type epitaxial layer 10 has a significant influence on a property of other component, thereby making it difficult to increase the thickness of the N-type epitaxial layer 10. Further, when the thickness of the N− type epitaxial layer 10 increases, the parasitic resistivity tends to increase due to the configuration of the cathode drawn through the embedded diffusion layer 12 and the N− diffusion layer 14, thereby decreasing a current capability in a forward direction.
In view of the problems described above, an object of the present invention is to provide a Schottky diode and a method of producing a Schottky diode capable of solving the problems of the conventional method of producing the Schottky diode. In the present invention, it is possible to produce the Schottky diode capable of arbitrarily obtaining a desirable reverse voltage resistance.
Further objects and advantages of the invention will be apparent from the following description of the invention.